The study will enroll 3 different cohorts of patients in parallel. Cohort A will enroll patients scheduled to undergo craniotomy and resection of newly diagnosed gliomas (both low and high grade). Patients in cohort A will be treated with crenolanib (CP-868,596) (300mg once daily, on an empty stomach) in the neo-adjuvant setting for a minimum of 3 days prior to surgical resection of their tumor mass. Twelve patients will be accrued on this neo-adjuvant cohort that will allow us to assess the ability of crenolanib (CP-868,596) to penetrate the tumor, not only in grade 3 and 4 gliomas (anaplastic astrocytomas and glioblastomas) that have a leaky BBB, but also in grade 2 gliomas (low grade gliomas) that tend to have a more intact blood-brain barrier (BBB).